DESCRIPTION: (Investigator's Abstract) The authors' idea is to make a fluorescent marker for neovascularization. Specifically, they want to stain new blood vessels with a fluorescent analogue of fluorescein. This would be useful in assessing diabetic retinal changes and also in limited subsets of age related macular degeneration. One of the authors has found a specific marker for neovascularization, being UPA. They then propose to find and develop a fluorescein compound, specifically to label the UPA present on new vessels. Two classes have been proposed with some apparent preliminary success: (1) Amiloride plus fluorescein (Amiloride has UPA specificity and inhibitory properties) and (2) amino fluorescein (has less avid binding of UPA but some specificity). The authors will then test these compounds four ways: (1) protease inhibition for UPA, TPA, a variety of other proteases, (2) the dissociative constant to find usefulness of the drug, (3) albumin binding to check fluorescence as well as to check any change in emission and absorption properties of the new compound, and (4) test its binding to UPA in the wounded endothelial cell monolayer culture system.